1. Field of the Invention
The present invention relates to a wafer processing method used to facilitate the handling of a thinly formed wafer.
2. Related Art
A wafer having a plurality of devices such as IC and LSI formed on its surface is divided into parts of the devices individually by using a dicing unit, and the resultant devices are widely used by being incorporated into various kinds of electronic equipment. In order to reduce the dimensions and weight of the electronic equipment, the wafer not yet divided into parts corresponding to the individual devices is ground at a rear surface thereof, and the thickness of the wafer is set to, for example, 100 μm to 50 μm.
When the wafer becomes thin due to the grinding operation therefor, the rigidity of the wafer is lost, so that the handling of the wafer in a later step becomes difficult. For example, coating the rear surface of the wafer for conducting a probe test on the wafer with a metal film of gold, silver and titanium becomes difficult. Therefore, it becomes difficult to conduct an electric test on the devices. Techniques for grinding the rear surface of the wafer with a support member bonded to the outer surface thereof have also been proposed (for example, refer to JP-A-2004-22634 and JP-A-2003-209083).
However, when a support member is bonded to the outer surface of the wafer, it becomes necessary to peel off the same later, and, even after the support member is peeled off, the adhesive agent remains in some cases on the devices formed on the outer surface of the wafer. In order to completely remove the adhesive agent, a troublesome operation is needed. The handling of the wafer becomes difficult in this respect as well.